Face clutch



Sept. 11, 1945. E. WILDHABER FACE CLUTCH Original Filed Dec. 21,1942 3Sheets-Sheet 1 has Fly

6 flnvenfov ERNEST W/LDHABEQ Sept. 1 l, 1945.

E. WILDHABER FACE CLUTCH Original Filed Dec. 21, 1942 3 Sheets-Sheet 2FA :17 Jay/a V 1.9 nventor ZEN/557' MAD/M552 p 1945. E. WILDHABER2,384,584

FACE CLUTCH Original Filed Dec. 2 l, 1942 3 Sheets-Sheet 3 nwnt or 3ERNEST WILD/#1552.

ttovneg Patented Sept. 11,, 1945 UNITED STATES PATENT OFFICE FACE CLUTCHErnest Wildhaber, Brighton, N. Y., assignor to Gleason Works, Rochester,N. Y., a corporation of New York 15 Claims.

The present inventior. relates to toothed face clutches and to methodsand apparatus for pro ducing such clutches. In a more particular aspect,the invention relates to the construction and production of clash-typetoothed face clutches, that is, clutches whose members are adapted to beengaged while the driver, at least, is rotating. The present applicationis a division of my copending application Serial No. 469,- 610, filedDecember 21, 1942, and deals specifically with my novel form of clutch.

Since the teeth and tooth spaces of thetwo engaging members of aclash-type clutch are not always in exact register when the clutchmembers are moved into engagement, their teeth are chamfered tofacilitate engagement. The chamfered parts of the teeth of the clutchmembers have to carry the loads at the beginning of engagement of theclutch members, and since these loads are high, shock loads, it isimportant that the,

portions of the teeth can stand and carry heavy loads.

A primary object of the present invention is to provide a toothed faceclutch which will have correct tooth chamfer and be capable of carryingheavy loads even when only the chamfered portions of the teeth of themating clutch members are in engagement. To this end, it is one aim ofthe invention to provide a toothed face clutch whose members have thechamfered portions of their teeth so shaped that they contact midway ofthe length of the chamfered portions and, if desired, along the wholelength thereof in all positions of partial engagement of the clutchmembers as the clutch members move into full engagement.

A further object of the invention is to provide an improved type ofchamfer surface for toothed face clutch members through which contact ofthe chamfer surfaces midway of the tooth length, or if desired, alongthe whole of the tooth length may be obtained exactly and withoutrelying on approximate shapes.

Another object of the invention is to provide a clash-type face clutchin which the chamfered portions of teeth of the two members areconiugate to one another.

A further object of the invention is to provide mating clash-type faceclutch members in which the chamfered portions of the teeth of onemember are form-cut and the chamfered portions of the teeth of the othermember are generated conjugate to the form-cut chamfered portions of thefirst member.

Other objects of the invention will be apparent hereinafter from thespecification and from the recital of the appended claims.

Toothed face clutch members constructed according'to the preferredembodiment of the present invention have longitudinally curved sidetooth surfaces and longitudinally curved chamfered portions. The sidetooth surfacesof both members are surfaces of revolution. The chamferedportions of the teeth of one member are surfaces of revolution coaxialwith the side tooth surfaces of that member, while the chamberedportions of the teeth of the other member are helicoidal surfacesconjugate to the chamfered portions of the teeth of its mate. The term"helicoidal surface is used in this application in a broad sense todescribe a surface enveloped by a surface of revolution which movesalong and about an axis, usually with a varying ratio of angular toaxial motion.

Preferably, opposite sides of spaced teeth of each member of the pairare cut and chamfered in a single operation. Opposite sides of spacedteeth of one member and the chamfered portions at the correspondingsides of said spaced teeth may be made parts of coaxial longitudinallyconcave surfaces of revolution, while opposite sides of spaced teeth ofthe other member may be made parts of a common longitudinally convexsurface of revolution. The chamfered surfaces at the corresponding sidesof the teeth of this latter member may be made parts of longitudinallyconvex helicoidal surfaces conjugate to the chamfered surfaces of themating clutch member.

Several different embodiments of the invention are illustrated in theaccompanying drawings in which:

Fig. 1 is a sectional view showing a pair of toothed face clutch membersmade according to one embodiment of this invention in eng ement, thesection being taken in a mean plane, hereinafter referred to as thepitch plane, which is perpendicular to the clutch axis;

Fig. 2 is a fragmentary elevational view of the pair of engaging clutchmembers;

Fig. 3 is a diagrammatic view, showing one of the clutch members partlyin section in the pitch plane and partly in plan, and illustrating theprinciples underlying the cutting and chamfering of the teeth of thismember;

Fig. 4 is a part elevational, part sectional view, further illustratingone way in which the teeth i at 1'0 and 'H.

of this clutch member may be simultaneously cut and chamfered;

Figs. 5 and 6 are views similar to Figs. 3 and 4. respectively, showingthe mating clutch member and illustrating one way of cutting andchamfering the teeth of this mating clutch member;

Fig. 'I is a fragmentary elevational view, showing the pair of matingclutch members being moved into engagement and illustrating theconjugacy of the'chamfered portions of the teeth of the two clutchmembers;

Fig. 8 is a fragmentary axial sectional view showing two face millcutters such as may be employed for cutting the two members of theclutch pair, respectively, and showing the relationship which existsbetween these two cutters;

Fig. 9 is a view on an enlarged scale of matching blades of the twocutters, further illustratin the relationship in construction whichexists between the cutters;

Figs. 10 to 19 inclusive are diagrammatic views illustrating successivesteps in the chamfering and cutting of opposite sides of spaced teeth ofa clutch member according to one embodiment of this invention, Figs. 10to 14 inclusive being views of the cutting and chamfering of one side ofa tooth of the clutch member, and Figs. 15 to 19 inclusive being viewsof the cutting and chamfering of the opposite side of a spaced tooth ofthe clutch member;

Fig. 20 is a normal sectional view on an enlarged scale of a tooth of aclutch member made according to a modification of this invention;

Fig. 21 is a similar view showing a tooth of a employed in thechamfering and cutting of this clutch member; and

Fig. 26 is a fragmentary elevational view of one member of a clutch pairmade according to this invention, illustrating particularly thecharacter of the chamfered portions of the tooth surfaces of this clutchmember.

Reference will be had first to the embodiment of the inventionillustrated in Figs. 1 to 19 in-.

elusive. Here 60 and Si denote, respectively, the two members of aclutch pair. The member 60 has teeth 62 which extend generally radiallyof the clutch axis 63 and whose opposite sides 64 and 65 arelongitudinally concave. The mating clutch member 6| has teeth 66 whichextend gen erally radially of the clutch axis 63 and whose oppositesides 61 and 68 are longitudinally convex.

The teeth 62 of member 60 are chamfered along their top edges on bothsides as denoted The teeth 66 of member 6| are chamfered along their topedges on both sides as denoted at 12 and 13.

The sides of the teeth of both clutch members are of zero pressure anglein the instance shown, that is,- the profiles of the sides 64 and 65 and61 and 66 of the teeth of both members extend in the direction of theclutch axis 63. In the instance shown, the sides of the teeth of bothclutch members are cylindrical surfaces parallel to clutch axis 63.Moreover, opposite sides of spaced teeth of each clutch member areportions of a common cylindrical surface. Thus, opposite sides 64a and65b of the teeth 62a and 62b, respectively, of clutch member 60 areparts of a common cylindrical surface whose axis is at 15 and isparallel to the clutch axis 63. Likewise, opposite sides 68a and 61b ofspaced teeth 66a and 66b, respectively, of clutch member 6i are portionsof a common convex cylindrical surface whose axis is at 16 parallel toclutch axis 63.

The chamfered portions 10 and H of the teeth of the clutch member 60 aresurfaces of revolution concentric with the corresponding sides of theteeth. Thus, the chamfered portions 10a and Nb at opposite sides of theteeth 62a and 6217, respectively, are longitudinally concave surfaces ofrevolution of convex profile shape whose common axis is at- 15. Thechamfered portions 12 and '13 of clutch member 6i are on the other handhelicoidal surfaces of varying lead conjugate to the chamfered portionsof the teeth of the clutch member 60. They are of longitudinally convexshape and of convex profile shape. A portion of the clutch member 6| isshown on an enlarged scale in Fig. 26. It will be noted that theinclination to the clutch axis of the chamfered portions 12 and 13 ofthe teeth increases with increasing radial distance from the clutchaxis. Thus the profile 14 at the outer end of the chamfered surface 13hat a greater inclination to the tooth side 61 than the profile 14' atthe inner end of the chamfered surface.

For cutting and chamfering the teeth of clutch member 60, a face millcutter (Figs. 4, 8 and 9) may be used. The blades 8| of this cutter arearranged circularly about the axis 82 of the cutter and have cuttingportions which project beyond one side face of the cutter in the generaldirection of the axis of the cutter. The blades 81 may be all outsidecutting blades, and may have a straight side-cutting edge 83 of zeropressure angle, a concave chamfering edge 84, a tip cutting edge and a.round 86 which connects the side-cutting edge 83 with the tip-cuttingedge 85. The concave chamfering edge lies below the side-cutting edgeadjacent the shank or body portion of the blade. The front faces of theblades may be sharpened in usual manner with the side rake'and theoutside surfaces of the blades may be relieved with a combined radialand axial relief to provide keen outside cutting and keen chamferingedges. The clearance or non-cutting sides of the blades may be of anysuitable shape.

The cutter 80 is preferably positioned to cut simultaneously in twospaced tooth zones of the work. The cutter is so positioned that itsaxis 82 is parallel to the axis 63 of the work and coincides with theaxis '15 of the tooth surfaces to be cut on the work. Cutting iseffected by rotating the cutter 80 on itsaxis 82 while holding the work60 stationary on its axis 63 and while effecting a relative depthwisefeed movement between the cutter and the work until full depth positionis reached. The depthwise feed movement may be in the direction of theaxis 63 of the work or it may be in a direction inclined to said axis.In full depth position, the straight side-cutting edges 83 (Fig. 9) ofthe cutter will sweep out and form opposite sides 64 and 65 on spacedteeth of the work which are coaxial and longitudinally concavecylindrical surfaces, while the concave chamfering edges 84 of thecutter will sweep out and form chamfer surfaces II and H of convexprofile at these same sides of the spaced teeth of the work which arecoaxial with one another and with said sides of the teeth as alreadydescribed. 18 denotes the path of a point in the chamfering edge of thetool and Ill the path of a point in the side-cutting edge of the tool atfull depth.

When a pair of tooth sides have been cut and chamfered, the cutter iswithdrawn from engagement with the work and the work indexed. Then thecycle begins anew. Thus the tooth sides and chamfer surfaces of theclutch member 68 may be produced simultaneously in a iorm ing operationand in a. rapid and efflcient process.

The form-cutting method used in cutting and chamfering the teeth ofclutch member 88 cannot be applied to the cutting and chamfering of theteeth of the mating clutch member Sl, for if the chamfer surfaces oi"both members were formcut, the chamfered portions of mating teeth wouldcontact only at the outer ends of the teeth as the clutch members weremoved into engagement, and the chamfered portions accordingly could notcarry heavy loads. The present invention provldes. however, a way forchamfering the teeth of the clutch member so that any desired amountlengthwise contact can be obtained between the engaging. clutch membersas they move into engagement. This contact may extend along the hiscontact is obtained by generating cred portions 32 and it of the teethmember 63 so that they have profile ate to the profile shapes of the oneit and ii of the teeth of J re nber 5t and so that their lengthmatch toany desired extent the pes of the chami'ered portions oi has a pluralityof insidecutoi the cutter and which have cutting s projecting beyond oneside face of the he general direction of the axis 92 or The blades tihave straight insideges t3, chamfering edges st, and tipes... Theside-cutting edges 93 may ssure angle or of slight negative c axis 92.The charnffering edges es dges of cutter t0, the chamfering 25:1 of thecutter 9d are arranged adjacent s of these blades instead of adjacentthe portions of the blades. In fact, the chamedges {it of blades illconnect the sideedges 93 of the blades with the tip-out dges 95 thereof.

convex chamfering edge 9% of a-blade 99 has same profile shape as theconvex chain fer surface it or ii of clutch member 863, that it acircular arc of the some radii'zs $38 as the concave chamfering edge t tof a blade 25 of cutter tit. It will be seen, therefore, that when thecutter til is rotated on its axis 92, it embodies the chamiered portionsof clutch member 68. 4

To generate the required chamfer on the teeth of the clutch member 68,the cutter so is rotated on its axis in engagement with the work while arelative feedmovement is eflected between the that is. of slightnegative incline,

v which. are arranged circuiariy shout cutter and the work about theclutch axis 63 and in the direction of said axis. rue motion produced isas if the clutch member N were contacting at various points along theheight of the chamfered surfaces oi its teeth with the chamferedsurfaces 01 the clutch member 5| as the two clutch members are movinginto engagement. In other words, in cutting the chamfered portions ofthe teeth of clutch member 65, the cutter 80, which represents thechamtered portion of a tooth of the clutch member '0, assumes suchpositions relative to the work as are assumedby the chamiered portionsoi a tooth of the clutch member 88 as the chami'ered portion of thattooth engages with and moves over the chamferedpore tion of a matingtooth of clutch member 66 during movement of the two clutch members intoengagement. One of the positions of partial engagement oi the two clutchmembers is shown in Fig. 7.

The relationship of the cutters 8b and to for cutting the two clutchmembers is clearly illustrated in Figs. 8 and 9. It is seen that theconvex chamfering edge 94 of a blade 9| oi cutter 99 matches the concavechamfering edge at of a blade El of cutter 58. Moreover, the convexchamfering profile 95 is an arc of the identical circle but preferablyis made to extend slightly beyond the concave chamiering edge Thestraight side-cutting edges t3 and 93 of the two blades need not match.in fact, the straight sidecutting edge es of Telade 9! is siightlyinclined to the straight side-cutting edge 83 of blade 88. Due

to the depthwlse feed, the sides as well as the chemfer surfaces of theteeth of clutch member 88 are formed by the convex cutting edges 85herein zeierrerl as chamfering edges.

The inside cutting diameter of cutter 96 will a as the outside cuttingdiameter of to if mating chamter surfaces and mating surfaces the twoclutch members are to have :fell contact, but lengthwise Knismawh of hischemise and mating side surfaces can be obtained by 'xising cutter oismaller inside diem Tao out clutch member 33 and shipping less teethbetween the two testis zones in which this cutter operates.

in cutting the chemfered portions of clutch member iii, the rotationabout the clutch axis $8 is usually performed by the work and the feedmovement in the direction of theclutch ants also performed by the work.There is a definite coordination required between the rotation about theclutch axis and the feed lengthwise of this axis. The requiredcoordination may be determined to correspond to assumed mean chemierprofiles, for instance, by layout.

The cham'Zered surfaces i2 and it produced are heilcoidal surfaces,usually helieoidal surfaces of varying lead. The rotary motion oi thework need take place only while a charniered surface is being cut. Thesides 6? and 83 of the teeth may be out with the work stationary bydepthieed of the rotating cutter into the work. In the preferredembodiment of the invention, a face mill cutter K d is employed whichis: of suficiently large diameter to operate in two spaced tooth zonesof the work simultaneously. The chernfered part at one side of a toothof the work is cut during in-ieed while th blank is being rotated intime with the in-feed movement. Then the rotation oi the blank isstopped but the in-feed is continued to cause the cutter to cutsimultaneously the side of the tooth previously chamtered and theopposite side of a spaced tooth of the work as portionsof a commonsurface of revolution.- Then the cutter is withdrawn and when it hasbeen partially withdrawn, the work rotation commences again so thatduring the last part of the withdrawal motion, the cutter will chamferthe last named tooth on the same side as has been cut.

Different relative angular positions of the cutter about the clutch axisduring cutting and 'chamfering of opposite sides of spaced-teeth ofclutch member ii are shown diagrammatically in Fig. 5. The ohamferedportion 13b of tooth 86b of clutch member ii is being produced when theaxis of the cutter is at O2 and the cutter has been partially fed intodepth. The path of a point in the cutting edge of the tool for thisposition is denoted at 01'. The side surface "b of tooth 88b and theopposite side surface Ila of tooth 66a spaced from tooth Bib are formedwhen the cutter axis is in mean position 92, and

,the cutter is'moving to full-depth position. The

path of said. point in the cutting edge of the tool for this position isdenoted at 81. Thechamfeted surface 12a of .tooth in is being producedwhen the cutter axis is at position 92" and the cutter is beingpartially withdrawn. 9?" denotes the path of the same cutting point whenthe cutter is at this cutting position. In this way. the chamferedportion of one side of a tooth and subsequently the opposite sides ofspaced teeth of clutch member 80 are cut during the in-feed. while theremaining chamfered pore tion is produced during the out-feed.

The cutting and chamfering cycle for clutch member BI is furtherillustrated in Figs. is to 19 inclusive. Figs. 10 to 14 inclusiveillustrate the'cutting action which takes place in one zone of cuttingengagement, namely, in the cutting and chamiering at one side of a tooth88b, and these are figures looking from the inside of the clutchoutwardly. Figs. 15 to 19 inclusive illustrate the cutting action whichtakes place in the other zone of cutting engagement, namely, in thecutting and chamfering at one side of tooth 89a, and these views arelooking from the outside of the clutch inwardly. The rounded chamieringedges 96 oi the cutting blades en, therefore, are at the right in bothinstances.

Fig. 10 shows the start of the cut on the rounded chamfer surface 13b oftooth 6%. The

i final shape of the tooth space 6911 adjacent the tooth side 16b isshown in dotted lines. While the cutter is cutting in the tooth space69b of the blank, it is also cutting inthe tooth, space "a. The start ofthe cut in the latter tooth space is shown in Fig. 15. As the rotatingcutter is fed relatively depthwise into the blank, the

Then the rotation about the work axis begins again, and as the cuttertravels outwardly from the position of Figs. 13 and 18 to the positionof Figs. 14 and 19, it produces the chamfered surface 12a. of tooth 66a.As soon as the cutter has moved clear of the work, the blank is indexed.Then the cutter is fed back into engagement with the work and the cycleof chamfering and cutting opposite sides of spaced teeth of the workbegins anew.

In Figs. 10 to 19 inclusive, dotted line I00 denotesthe path of thecenters of chamfering edges 94 of cutter 90 at one tooth zone of thework, and dotted line m denotes the path of these same centers in theother tooth zone of the work during the cutting and chamfering cycle.

Various types of chamfer may be obtained with the method of the presentinvention. On form of chamfer surface that can be produced isillustrated in Figs. 1 to 19 inclusive. Other forms are shown in Figs.20 and 21. In Fig. 20, I06 denotes the profile of the chamfered surfaceat one side of tooth I06. This profile is a circular arc whose center isat Iill. Such a chamber surface joins the straight zero pressure angletooth side its smoothly without angle. The center It? may be midwaybetween the sides Hi8 and I09 of the tooth tilt and the top of the toothmay be fully rounded, as shown. In Fig. 21, the chamier surface M6 isagain of circular arcuate profile shape, but its profile shape is oflarger radius being centered at iii. The chamfer surfaces M5 and IE0 atthe sides of the tooth ilfi'may join the respective tooth sides I I8 orI I9 at slight angles. of course, the chamfer surfaces need not he ofcircular arcuate profile shape but may be of any desired profilecurvature.

"Ihe clutch members and ii of Figs. 1 to 6 inclusive have teeth ofuniform height from end to end and the root lines of the teeth lie in aplane perpendicular to the clutch axis. A more preferable embodiment ofthe invention is illustrated in Figs. 22 to 25 inclusive where theclutch members have tooth spaces whose root surfaces are conicalsurfaces and are inclined to the clutch axis. The clutch members ofFigs. 22 to 25 have the added advantage that they may be cut withcutters having side-cutting edges of positive pressure angle. A

Cutters, like the cutters 80 and Bil, which are used in cutting theclutch members 60 and BI,

blank is rotated on its axis in time with the I depthwise feed movementto generate the chamfer surface 13b. When the cutter reaches the edges Nof the cutter will sweepout and produce the rounded fillets which jointhese tooth sides with the bottoms of the tooth spaces "b and "a. Thenthe withdrawal motion starts. A the positlonindicated in Figs. 13 and18, the cutter has been withdrawn far enough for the chamfering of theside Ila of tooth a to start.

have side-cutting edges of zero or negative pressure angle. Hence, theymust be relieved radicaily as well as axially in order to providecutting clearance. After sharpening, moreover, the blades of suchcutters must be readjusted radially individually in order to maintainthe cutter diameter. Such an adjustment is objectionable and can beavoided by use of cutters having sidecutiiing edges of positive pressureangle, for blades having side surfaces of positive pressure angle can beaxially relieved and axial adjust ment of the cutter itself, aftersharpening of the blades, will properly readjust all the blades of thecutter simultaneously.

In Figs. 22 to 25 inclusive, one member of a clutch pair is denoted atI20 and the mating member at Hi. The clutch'memberliil iscut with a facemill cutter I25 which has a plurality of circularly arranged cuttingblades I2. Each blade has an outside cutting edge I21, a chamfering'edge I29, and a tip-cutting edge Ill. The outside cutting edge is ofstraight proiiie and positive pressure angle or inclination to thecutter axis I28. The chamfering edge I29 is of concave profile shape andlies adjacent to the shank of the blade. The tip-cutting edge I30 ispreferably made perpendicular to the sidecutting edge I21 and is,therefore, inclined with reference to the cutter axis I28 at other thanright angles. The highest part of the tip-cutting edge is at its outerend.

For cutting the toothed face clutch member I20 whose tooth sides I34 andI35 are of zero pressure angle, the cutter I25 is tilted inwardly withreference to the work. Opposite sides I34 and I35 of spaced teeth i32 ofthe clutch member I20 are chamiered and cut in a single cycle ofoperation by rotating the cutter I25 on its axis 528 while holding thework I28 stationary On its axis and effecting relative depthwise feedmovement between the cutter and the work preferably in a direction 236(Fig. 23) slightly inclined to the direction of clutch axis I33.

The tooth sides and the chamfered surfaces produced on the clutch memberare counterparts of the chamfering and cutting surfaces of the cutterI25. Both sides of the teeth of the clutch member are of longitudinallyconcave shape and the chamfered portions at opposite sides of the teethare of longitudinally concave shape. The sides of the teeth are ofstraight profile and zero pressure angle, while the chamfered portionsare of convex profile.

The dot-dash line 31 in Fig. 22 denotes the path of a point in theside-cutting edge of the tool at full depth position. Opposite sides ofspaced teeth as, for instance, the sides I34a and I35b of the teeth I32aand I32b, are portions of a common conical surface whose axis coincideswith the cutter axis I28 in full depth position of the cutter andintersects the clutch axis I33. The chamfered surfaces I36a. and I351)at these same sides of these spaced teeth are alsoportions of surfacesof revolution coaxial with the conical sides of the teeth. Thebottoms-I39 of the tooth spaces of the clutch member are inclined to theclutch axis and are substantially conical surfaces coaxial with theclutch member.

The mating clutch member I2I may be cut with a face mill cutter I45whose blades I46 are arranged circularly about its axis I48. Theseblades (Fig. 25) have inside cutting edges I41, chamfering edges I49,and tip-cutting edges I50. The inside cutting edges I41 are of positivepressure angle and inclined to the cutter axis I48. The tip cutti'ngedges I50 are perpendicular to the side-cutting edges I41 and thereforeinclined at other than right angles to the axis I48 of the cutter. Theyare highest at their inner ends. The chamfering edges I49 are of convexprofile shape and connect the side-cutting edges I41 with thetip-cutting edges I50 of the blades. The profile of the convexchamfering edge I49 of a blade I46 of cutter I45 matches the concaveprofile of a chamfering edge I29 of cutter I25 so that the convexchamfering portions of cutter I45 represent the chamfered top of a toothof clutch member I20 as the cutter rotates on its axis.

The cutter I45 may be of the same inside diameter as the outsidediameter of the cutter I25,

but. if it is desired to have lengthwise mismatch cutter I45, convextooth sides I51 and I58 will be cut on teeth I56 of the clutch memberI2I which are more curved lengthwise than the concave sides I34 and I35of the mating clutch member I20. A smaller angle will be skipped betweenthe two tooth zones operated upon by the cutter I45 than is skippedbetween the two tooth zones operated upon by the cutter I25.

For cutting the clutch member I2I, the cutter I45 is tilted outwardlywith reference to the clutchmember I2I to out side tooth surfaces ofzero pressure angle on the clutch member.

The teeth of clutch member I2I are chamfered and have their sides cut inthe same way as the teeth of the clutchmember III. The cutter I45 isrotated in engagement with the work and a relative feed motion isproduced about and in the direction or the clutch axis I33 to generatethe chamfered portions I53 and I60 of the teeth. The depthwise feedmovement is in the direction of the arrow 562 if'imparted to the work.When the cnamfered portion at one side of a tooth has been completed,the rotational movement of the work is stopped, but the relativedepthwise feed movement continues until full depth position is reached.During this depthwise feed movement, opposite sides of spaced teeth ofthe clutch member are cut as parts of a common convex cylindricalsurface of revolution coaxial with the cutter axis m8. Then the cutter1S withdrawn from engagement with the work. When the cutter has beenwithdrawn 2. sutlicient distance from full-depth position, the workrotation is restarted and, during the further withdrawal motion, thechamfered portion lbu of a tooth is cut. When the cutter is clear of thework, the work is indexed.

The relative feed motion about the clutch axis is illustrated in Fig. 24by the movement of a point in the cutter axis I48. when this point is.at I55, the chamfered surface I59b of tooth I501) is being generated,and the path of a point in the cutting edge of the cutter is at I54.When the said point in the cutter axis is at I55, the mean cutter pathis at I54 and the sides I51b and lbua of spaced teeth I360 and l5b'a areformed. The cnamier Iona on tooth I561: is generated during thewithdrawal movement of the cutter when the cutter is at partial depthengagement. When the said point in the cutter axis is at I55" and thepath ofa point in the cutting surface is at I54", the cnam-fered portionIIiIIa of tooth I53a isrbeing generated.

Preferably, the smaller diameter cutter I45 is designed so that its axisI48 may be inclined to the clutch axis I33 at a smaller angle than theangle of inclination of the cutter axis I28 to clutch axis I33 duringproduction of the clutch member IzII. Thus the root lines IBI of thetooth spaces cut in the clutch member I2I may be inclined to the clutchaxis I33 at approximately the same angle as are the bottoms I39 of thetooth spaces of the clutch member I20.

The tops of the teeth of the two clutch members I20 and I2I may be planesurfaces perpendicular to the clutch axis I33, but preferably the topsof the teeth of clutch member I20 are shaped, as shown, to lie in anexternal conical surface coaxial with the clutch and the tops of theteeth of clutch member I2I are shaped, as shown, to

lie in an internal conical surface coaxial with the clutch. By properlyselecting the angles of these conical top surfaces. the teeth or bothclutch members can be made of uniform height from at the tooth ends.With the smaller diameter endtoend.

While the invention has been described in con-f nection with clutchmembers having longitudi nally curved teeth, it will lbe understood thatin its broad aspects it is also applicable to clutches havinglongitudinally straight teeth. Further it will be understood that it isnot limited in application to clutch members having side tooth surfacesof zero pressure angle but may be applied also to clutch members ofpositive pressure angle although ordinarily its use is confined toclutch members of low pressure angle. Still further it will beunderstood thatwhile I have described the invention in connection withclutch pairs in which one member has side tooth surfaces that arelongitudinally concave and the other member has side tooth surfaces thatare longitudinally convex, both members may be made with longitudinallyconvex side tooth surfaces if quite restricted localization of toothcontact is desired.

Indeed, while a number of different embodiments of the invention havebeen described, it will be understood that the invention is capable [ofstill further modification, and this application is intended to coverany variations, uses, or adaptations of the invention following, ingeneral, the principles of the invention and including such departuresfrom the present disclosure as come within known or customary practicein the art to which the invention pertains and as may be applied to theessential features hereinbefore set forth and as fall within the scopeof the invention or the limits of the appended claims.

Having thus described my invention, what I claim is:

1. A toothed face clutch member having longitudinally curved teeth whichare chamfered along their top edges, the chamfered portions of surfaces.

2. A toothed face clutch member having lonitudinally curved teeth whichare chamfered along their top edges, the chamfered portions of the teethbeing helicoidal surfaces of convex profile shape and of varying lead.

3. A pair of engaging toothed face clutch mem- 1bers, each of which hasteeth that are chamfered along their top edges, the chamfered portionsof the teeth of one member being surfaces of constant profile shape fromone end to the other, and the chamfered portions of the teeth of theother member being helicoidal surfaces conjugate to the chamferedsurfaces of the first member.

4. A pair of engaging toothed face clutch members, each of which haslongitudinally curvedteeth that are chamfered along their top edges,

the chamfered portions of the teeth of one memher being surfaces ofrevolution, and the chamfered portions of the teeth of the other memberbeing helicoidal surfaces conjugate to the chamfered surfaces of thefirst member.

5. A pair of engaging toothed face clutch mem- ;6. A 'pair'of engagingtoothed face clutch members, each of'which has longitudinally curvedteeth chamfered along theirtop edges, the chasm the teeth beinglongitudinally curved helicoidal helicoidal surfaces conjugate to thechamfered surfaces of the mating member.

7. A pair of engaging toothed face clutch members, each of which haslongitudinally curved teeth which are chamfered along their top edges,the chamfered portions of the teeth of one member being surfaces ofconvex profile shape conhaste to the chamfered surfaces of the matemember. I

8. A pair of engaging toothed face clutch members, each of which haslongitudinally curved teeth that are chamfered along their to edges, theside'surfaces and chamfered portions of the teeth of one of said membersbeing coaxial surfaces of revolution, and the side surfaces of the teethof the other member being also surfaces of revolution, but the chamferedportions of the teeth of the latter member being helicoidal surfacesconjugate to the chamfered surfaces of the first member.

.9. A pair of engaging toothed face clutch mem-- bers, each of which haslongitudinally curved teeth that are chamfered along their top edges,opposite sides of spaced teeth of one member being longitudinallyconcave surfaces of revolution of straight profile shape, and oppositesides of spaced teeth of the other member being parts of a commonlongitudinally convex surface of revolution also of straight profileshape, the chamfered portions at opposite sides of spaced teeth of thefirst member being parts of a common surface of revolution of convexprofile shape coaxial with the corresponding sides of said member, andthe chamfered portions at opposite sides of spaced teeth of the othermember being helicoidal surfaces of convex profile shape conJugate'opposite sides of spaced teeth of both members being parts of commonconical surfaces, the

chamfered portions 'at opposite sides of spaced teeth of one memberbeing parts of a common surface of revolution coaxial with thecorresponding sides of said member, and the chamfered portions atopposite sides of spaced teeth of the other member being helicoidalsurfaces cone jugate to the ohamfered surfaces of'the first member.

. 12. A pair of engaging toothed face clutch members, each of which haslongitudinally curved teeth that are chamfered along their top edges,opposite sides of spaced teeth of one member-being longitudinallyconcave and parts offs 'ber's, each of which has teeth that arechamfered along their topedges, the chamfered portions of common conicalsurface, and opposite sides of spaced teeth of the other member beinglongitudinally convex and parts of common conical surfaces, thechamfered portions at opposite sides of spaced teeth of the first memberbeing parts of a common surface of revolution of convex profile shapecoaxial with the corresponding sides of said first member, and thechamfered portions at opposite sides of spaced teeth of the other memberbeing helicoidal-surfaces of varying lead and convexprofiloshapeconiugatetothoclmnfered fared ortions of the teeth of onemember 7'surfaces of the first membe the bottoms of the 14. A toothed face clutchmember having longi tudinally curved teeth which are chamfered alongtheir top edges, the chamfered portions of the teeth being of convexlengthwise and convex profile shapes and being heliccidal surfaces ofvaryin; lead whose inclination to the clutch axis increases from theinner to the outer ends 0! the teeth.

15. A pair of toothed face clutch members, each of .which haslongitudinally curved teeth and each of which has its teeth chamfered.along their top edges, the cnamfered portions at opposite sides ofspaced teeth of one member of the pair being parts 0!, common surfacesor revolution, and the chamiered portions 0! the teeth of the othermember oi the pair being longitudinal- 1y curved helicoidal surfaces orvarying lead whose inclination to the clutch axis increases from theouter to the inner ends of the teeth.

ERNEST WILDHABER.

